Diffusion in dense supercritical methane from quasi-elastic neutron scattering measurements.

ABSTRACT: Methane, the principal component of natural gas, is an important energy source and raw material for chemical reactions. It also plays a significant role in planetary physics, being one of the major constituents of giant planets. Here, we report measurements of the molecular self-diffusion coefficient of dense supercritical CH₄ reaching the freezing pressure. We find that the high-pressure behaviour of the self-diffusion coefficient measured by quasi-elastic neutron scattering at 300 K departs from that expected for a dense fluid of hard spheres and suggests a density-dependent molecular diameter. Breakdown of the Stokes-Einstein-Sutherland relation is observed and the experimental results suggest the existence of another scaling between self-diffusion coefficient D and shear vis

SUBMITTER: Ranieri U 

PROVIDER: S-EPMC8009954 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature